Research has continued on developing a thermal shape-memory blood clot filter for insertion into the human inferior vena cava to prevent pulmonary embolism. After extensively evaluating a series of filter designs a double-wire has now been developed and undergone initial in vitro and in vivo evaluation with promising results. In the coming year the design will be refined for maximum effectiveness. Possible thrombogenicity of the nitinol material will continue to be examined and we will look for evidence of toxicity of nitinol though none is evident thus far. When the filter design is shown to perform flawlessly in animal studies it is planned to seek the necessary approval and funding for application of the filter device to the human patient. A parallel study of the metallurgic properties of Nitinol is successfully characterizing the material relative to the manufacture of the alloy, its processing and its handling. This has contributed to the development of the filter and the system of catheters, guidewires and valves used to deliver the device into the vena cava.